Hong Kong Water Supply – Lam Tsuen Pipeline

December 22, 2020 Tymon Utilities

Tymon Mellor: As you walk down the path from Lead Mine Pass to Tai Po, you will see along the route a number of concrete blocks that once formed the pipe supports from some long abandoned water supply project. The location of the pipeline is isolated and there is no obvious scheme associated with the works. However, this was part of an early implementation of the lowland pumping scheme; transferring water from the rivers of the New Territories to the urban water supply network.

The year of 1955 received an average rainfall, but it was unevenly distributed with the wet season ending early in August, so extending the dry season. With expanding industry, new housing projects and large squatters areas, the water supply system could not keep up with demand. On the 26^th November, the domestic supply was reduced to 2.5 hours a day in an attempt to conserve the limited reserves[i]. The Public Works Department undertook a rapid review to identify new water sources, and two schemes were proposed:

pumping water from the Shing Mun River at Shatin into the Beacon Hill catchwater; and
pumping water from Lam Tsuen River in Tai Po to the Shing Mun Reservoir.

Within six months both schemes were operational and contributing to the Territory’s water supply.

Shing Mun Pumping Scheme

The Shing Mun scheme required the installation of around 1,200m of 200mm diameter pipe from the Shing Mun River up the hillside to the Beacon Hill catchwater. The water would then flow by gravity into Kowloon Reservoir and the water supply network. A diesel pump was sourced from the Rumsey Street salt water pumping scheme and was used to raise the water 150m up the hillside to the catchwater. The scheme was completed and commissioned on the 21^st December 1955, supplying an additional 800,000 gallons a day to Kowloon Reservoir.

The location of the pipeline has not been recorded, but looking at the 1963 aerial images of the area, there appears to be evidence of a pipeline above the village of Kak Tin. A pipeline along the alignment indicated would appear to match the noted pipeline length.

Lam Tsuen Pumping Scheme

The Lam Tsuen pipeline was a longer and more complex arrangement, requiring two intake pumps and three booster pumps along with over 5,000m of pipeline to transfer the water over the 400m high Lead Mine Pass.

New intake dams were constructed on the Lam Tsuen River and the Tai Po River, either side of Tai Po. Two sets of pumps were provided at the Lam Tsuen River intake, an electric pump formally used as a booster pump on the Aberdeen Trunk main and a diesel unit from the dismantled Government dredger. At the Tai Po River intake, a diesel pump procured for the new Tsuen Wan pumping station was utilised and two electric pumps from the same scheme were used as booster pumps along the pipeline. Two small electric pumps sourced from Tai Tam Tuk reservoir were used as the final booster below Lead Mine Pass from where the pumped water was discharged into the stream feeding Shing Mun Reservoir.

Using pipes varying in size from 300mm to 450mm diameter, the scheme was completed in February 1956 and provided an additional 2.5 million gallons of water a day.

During the summer of 1956, with ample rain available, the scheme was suspended for two months to install safety relief valves and replace the two small electric pumps below Lead Mine Pass with a larger electric pump. Once more, this was sourced from Tai Tam Tuk.

The installation of the relief valves resolved pressure surges that had been occurring during power failures causing numerous burst pipes. With the installation of the large pump, the capacity of the system was increased to 4.5 million gallons a day.

Success and Closure

During 1956, the two pump schemes combined provided 1,252 million gallons of additional water, of which 853 million gallons were delivered during the six dry months of October to March[ii].

With the advent of heavy rains and the commissioning of Tai Lam Chung Reservoir in 1957, the pump schemes were no longer required. The pipes were removed and the pumps returned to the Tsuen Wan Rumsey Street facilities[iii]. Leaving only the concrete pipe supports as a reminder of the scheme.

The Lowland Pumping Scheme

The success of the schemes demonstrated the benefit of locating new water sources in the north of the Territory and utilising a pipeline to deliver water. In 1960 a new 1.2m diameter pipeline was constructed from the Boundary to the Tai Lam Chung Reservoir catchwater, a distance of 16km. This pipeline was fed by a new pumping station near Man Kam To connecting to the Mainland supply and was supplemented from a second pumping station on the River Indus in the north of the New Territories. Pumping of the water from the Indus commenced on the 7^th October 1960 and from the new Shum Chun Reservoir across the border on the 5^th December, 1960, through an agreement to supply 5,000 million gallons a year[iv]. This would be the first of the Mainland water supply scheme, but its capacity was still insufficient for the needs of the growing Territory. What was needed was a very large reservoir. It was time for the Plover Cove Scheme.

Hong Kong Water Supply – Lam Tsuen Pipeline

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